The new $27.5 million bridge will span the Snoqualmie River just west of Carnation and approximately 165 feet upstream from the current historic bridge on Northeast Tolt Hill Road. The new bridge will be wider and safer for motorists and pedestrians, plus is designed to reduce river flooding in that location.

This is the largest construction project for the King County Road Services since the completion of the new Elliott Bridge in 2005. Construction of the new Tolt Bridge is expected to last for up to two years. The Roads Division is staging the construction to avoid fish-spawning seasons and to minimize traffic disruptions for local residents.

One of the goals is to keep Northeast Tolt Hill Road open to traffic as much as possible throughout construction. Motorists can expect one 2-3 week closure this summer, and then another in the spring of 2008. There could also be occasional short closures for maintenance work on the old bridge, but otherwise the road should remain open throughout the majority of the construction period.

The first activity at the project site will be removal of brush and some trees on the west side of the bridge near the intersection of Northeast Tolt Hill Road and West Snoqualmie River Road Northeast.

Early next month, the contractor will be placing a huge order for the steel that will go into the new bridge. The order is so large that project managers estimate it will take nine months to fabricate and then deliver to the site.

The county has been working to replace the Tolt Bridge for many years. Extra time was needed to gather funding for the costly project, negotiate agreements with numerous agencies on environmental issues, and to address residents’ concerns about the design of a bridge that would replace a community landmark.

The existing bridge is more than 80 years old and needs frequent maintenance, often requiring traffic closures. It has limited sight distance, a narrow roadway and restricted weight limits. It also does not meet current seismic, safety, or roadway design standards. In addition to constructing a modern bridge, this project will widen and realign Northeast Tolt Hill Road both east and west of the new bridge to increase sight distance and safety.

The plans call for a 970-foot-long bridge made up of two 300-foot-long trusses over the west side of the river and the river itself, and a concrete girder section on the east side.

The twin trusses will echo the historic look of the existing bridge. The new bridge will have a cast-in-place, 40-foot-wide concrete deck supported by six double-column concrete piers.

An eight-foot-wide shoulder for pedestrians and bicyclists will be added on both sides of Northeast Tolt Hill Road and the bridge. An open-rail type barrier will be built on both sides of the new bridge for safety.

For more information: http://www.metrokc.gov/kcdot/roads/cip/projectdetail.aspx?cipid=200394